@function breakpoint-next($name, $breakpoints: $grid-breakpoints, $breakpoint-names: map-keys($breakpoints)) {
  $n: index($breakpoint-names, $name);

  @return if($n != null and $n < length($breakpoint-names), nth($breakpoint-names, $n + 1), null);
}

@function breakpoint-min($name, $breakpoints: $grid-breakpoints) {
  $min: map-get($breakpoints, $name);

  @return if($min != 0, $min, null);
}

@function breakpoint-max($name, $breakpoints: $grid-breakpoints) {
  $next: breakpoint-next($name, $breakpoints);

  @return if($next, breakpoint-min($next, $breakpoints) - 0.02, null);
}

@mixin media-breakpoint-up($name, $breakpoints: $grid-breakpoints) {
  $min: breakpoint-min($name, $breakpoints);

  @if $min {
    @media (min-width: $min) {
      @content;
    }
  }

  @else {
    @content;
  }
}

@mixin media-breakpoint-down($name, $breakpoints: $grid-breakpoints) {
  $max: breakpoint-max($name, $breakpoints);

  @if $max {
    @media (max-width: $max) {
      @content;
    }
  }

  @else {
    @content;
  }
}

@mixin media-breakpoint-only($name, $breakpoints: $grid-breakpoints) {
  $min: breakpoint-min($name, $breakpoints);
  $max: breakpoint-max($name, $breakpoints);

  @if $min != null and $max != null {
    @media (min-width: $min) and (max-width: $max) {
      @content;
    }
  }

  @else if $max == null {
    @include media-breakpoint-up($name, $breakpoints) {
      @content;
    }
  }

  @else if $min == null {
    @include media-breakpoint-down($name, $breakpoints) {
      @content;
    }
  }
}
